Abstract:

A transmission of the present invention has an input member, an output
member, four planetary gear sets, a plurality of coupling members and a
plurality of torque transmitting devices. Each of the planetary gear sets
includes first, second and third members. The torque transmitting devices
may include clutches and brakes. The torque transmitting devices are
selectively engageable in combinations of at least two to establish at
least nine forward speed ratios and at least one reverse speed ratio.

Claims:

1. A transmission comprising:an input member;an output member;first,
second, third and fourth planetary gear sets each having first, second
and third members;a first interconnecting member continuously
interconnecting the first member of the first planetary gear set with
first member of the second planetary gear set;a second interconnecting
member continuously interconnecting the second member of the first
planetary gear set with the second member of the third planetary gear
set;a third interconnecting member continuously interconnecting the first
member of the second planetary gear set with the first member of the
third planetary gear set;a fourth interconnecting member continuously
interconnecting the third member of the second planetary gear set with
the second member of the third planetary gear set;a fifth interconnecting
member continuously interconnecting the third member of the third
planetary gear set with the third member of the fourth planetary gear
set; andsix torque transmitting devices selectively engageable to
interconnect one of the first, second, and third members with at least
one other of the first members, second members, third members, and a
stationary member, andwherein the torque transmitting devices are
selectively engageable in combinations of at least two to establish at
least nine forward speed ratios and at least one reverse speed ratio
between the input member and the output member.

2. The transmission of claim 1 wherein a first of the six torque
transmitting devices is selectively engageable to interconnect the input
member, the first member of the first planetary gear set, first member of
the second planetary gear set and the first member of the third planetary
gear set with the second member of the fourth planetary gear set.

3. The transmission of claim 2 wherein a second of the six torque
transmitting devices is selectively engageable to interconnect the second
member of the second planetary gear set with the first member of the
fourth planetary gear set and the output member.

4. The transmission of claim 3 wherein a third of the six torque
transmitting devices is selectively engageable to interconnect the second
member of the first planetary gear set, the second member of the third
planetary gear set and the third member of the second planetary gear set
with the stationary member.

5. The transmission of claim 4 wherein a fourth of the six torque
transmitting devices is selectively engageable to interconnect the third
member of the first planetary gear set with the stationary member.

6. The transmission of claim 5 wherein a fifth of the six torque
transmitting devices is selectively engageable to interconnect the second
member of the fourth planetary gear set with the stationary member.

7. The transmission of claim 6 wherein a sixth of the six torque
transmitting devices is selectively engageable to interconnect the third
member of the third planetary gear set and the third member of the fourth
planetary gear set with the stationary member.

8. The transmission of claim 1 wherein the third member of the first
planetary gear set, the first member of the second planetary gear set,
the first member of the third planetary gear set and the third member of
the fourth planetary gear set are sun gears, the second member of the
first planetary gear set, the second member of the second planetary gear
set, the second member of the third planetary gear set and the first
member of the fourth planetary gear set are carrier members and the first
member of the first planetary gear set, third member of the second
planetary gear set, the third member of the third planetary gear set and
the second member of the fourth planetary gear set are ring gears.

9. The transmission of claim 1 wherein the input member is continuously
interconnected with the first member of the first planetary gear set, the
first member of the second planetary gear set, and the first member of
the third planetary gear set, and output member is continuously
interconnected with the first member of the fourth planetary gear set.

10. The transmission of claim 1 wherein four of the six torque
transmitting devices are brakes and two of the six torque transmitting
devices are clutches.

11. The transmission of claim 1 wherein the stationary member is a
transmission housing.

12. A transmission comprising:an input member;an output member;first,
second, third and fourth planetary gear sets each having first, second
and third members, wherein the input member is continuously
interconnected with the first member of the first planetary gear set, the
first member of the second planetary gear set, and the first member of
the third planetary gear set, and output member is continuously
interconnected with the first member of the fourth planetary gear set;a
first interconnecting member continuously interconnecting the first
member of the first planetary gear set with first member of the second
planetary gear set;a second interconnecting member continuously
interconnecting the second member of the first planetary gear set with
the second member of the third planetary gear set;a third interconnecting
member continuously interconnecting the first member of the second
planetary gear set with the first member of the third planetary gear
set;a fourth interconnecting member continuously interconnecting the
third member of the second planetary gear set with the second member of
the third planetary gear set;a fifth interconnecting member continuously
interconnecting the third member of the third planetary gear set with the
third member of the fourth planetary gear set;a first torque transmitting
device selectively engageable to interconnect the input member, the first
member of the first planetary gear set, first member of the second
planetary gear set and the first member of the third planetary gear set
with the second member of the fourth planetary gear set;a second torque
transmitting device selectively engageable to interconnect the second
member of the second planetary gear set with the first member of the
fourth planetary gear set and the output member;a third torque
transmitting device selectively engageable to interconnect the second
member of the first planetary gear set, the second member of the third
planetary gear set and the third member of the second planetary gear set
with the stationary member;a fourth torque transmitting device
selectively engageable to interconnect the third member of the first
planetary gear set with the stationary member;a fifth torque transmitting
device selectively engageable to interconnect the second member of the
fourth planetary gear set with the stationary member; anda sixth torque
transmitting device selectively engageable to interconnect the third
member of the third planetary gear set and the third member of the fourth
planetary gear set with the stationary member, andwherein the torque
transmitting devices are selectively engageable in combinations of at
least two to establish at least nine forward speed ratios and at least
one reverse speed ratio between the input member and the output member.

13. The transmission of claim 12 wherein the third member of the first
planetary gear set, the first member of the second planetary gear set,
the first member of the third planetary gear set and the third member of
the fourth planetary gear set are sun gears, the second member of the
first planetary gear set, the second member of the second planetary gear
set, the second member of the third planetary gear set and the first
member of the fourth planetary gear set are carrier members and the first
member of the first planetary gear set, third member of the second
planetary gear set, the third member of the third planetary gear set and
the second member of the fourth planetary gear set are ring gears.

14. The transmission of claim 12 wherein the stationary member is a
transmission housing.

15. A transmission comprising:an input member;an output member;first,
second, third and fourth planetary gear sets each having sun gears,
carrier members and ring gears, wherein the input member is continuously
interconnected with the ring gear member of the first planetary gear set,
the sun gear member of the second planetary gear set, and the sun gear
member of the third planetary gear set, and output member is continuously
interconnected with the carrier member of the fourth planetary gear set;a
first interconnecting member continuously interconnecting the ring gear
member of the first planetary gear set with sun gear member of the second
planetary gear set;a second interconnecting member continuously
interconnecting the carrier member of the first planetary gear set with
the ring of the second planetary gear set;a third interconnecting member
continuously interconnecting the sun gear member of the second planetary
gear set with the sun gear member of the third planetary gear set;a
fourth interconnecting member continuously interconnecting the ring gear
member of the second planetary gear set with the carrier member of the
third planetary gear set;a fifth interconnecting member continuously
interconnecting the ring gear member of the third planetary gear set with
the sun gear member of the fourth planetary gear set;a first torque
transmitting device selectively engageable to interconnect the input
member, the ring gear member of the first planetary gear set, sun gear
member of the second planetary gear set and the sun gear member of the
third planetary gear set with the ring gear member of the fourth
planetary gear set;a second torque transmitting device selectively
engageable to interconnect the carrier member of the second planetary
gear set with the carrier member of the fourth planetary gear set and the
output member;a third torque transmitting device selectively engageable
to interconnect the carrier member of the first planetary gear set, the
carrier member of the third planetary gear set and the ring gear member
of the second planetary gear set with the stationary member;a fourth
torque transmitting device selectively engageable to interconnect the sun
gear member of the first planetary gear set with the stationary member;a
fifth torque transmitting device selectively engageable to interconnect
the ring gear member of the fourth planetary gear set with the stationary
member; anda sixth torque transmitting device selectively engageable to
interconnect the ring gear member of the third planetary gear set and the
sun gear member of the fourth planetary gear set with the stationary
member, andwherein the torque transmitting devices are selectively
engageable in combinations of at least two to establish at least nine
forward speed ratios and at least one reverse speed ratio between the
input member and the output member.

16. The transmission of claim 15 wherein the stationary member is a
transmission housing.

Description:

FIELD

[0001]The invention relates generally to a multiple speed transmission
having a plurality of planetary gear sets and a plurality of torque
transmitting devices, and more particularly to a transmission having nine
or more speeds, four planetary gear sets and a plurality of torque
transmitting devices.

BACKGROUND

[0002]The statements in this section merely provide background information
related to the present disclosure and may or may not constitute prior
art.

[0003]A typical multiple speed transmission uses a combination of friction
clutches or brakes, planetary gear arrangements and fixed
interconnections to achieve a plurality of gear ratios. The number and
physical arrangement of the planetary gear sets, generally, are dictated
by packaging, cost and desired speed ratios.

[0004]While current transmissions achieve their intended purpose, the need
for new and improved transmission configurations which exhibit improved
performance, especially from the standpoints of efficiency,
responsiveness and smoothness and improved packaging, primarily reduced
size and weight, is essentially constant. Accordingly, there is a need
for an improved, cost-effective, compact multiple speed transmission.

SUMMARY

[0005]A transmission is provided having an input member, an output member,
four planetary gear sets, a plurality of coupling members and a plurality
of torque transmitting devices. Each of the planetary gear sets includes
first, second and third members. The torque transmitting devices are for
example clutches and brakes.

[0006]In an aspect of the present invention a transmission is provided
having an input member, an output member, a first, second, third and
fourth planetary gear sets each having sun gears, carrier members and
ring gears. The input member is continuously interconnected with the ring
gear member of the first planetary gear set, the sun gear member of the
second planetary gear set, and the sun gear member of the third planetary
gear set. The output member is selectively interconnected with the
carrier member of the fourth planetary gear set.

[0007]Additionally, a first interconnecting member continuously
interconnects the ring gear member of the first planetary gear set with
sun gear member of the second planetary gear set, a second
interconnecting member continuously interconnects the carrier member of
the first planetary gear set with the ring gear member of the second
planetary gear set, a third interconnecting member continuously
interconnects the sun gear member of the second planetary gear set with
the sun gear member of the third planetary gear set, a fourth
interconnecting member continuously interconnects the ring gear member of
the second planetary gear set with the carrier member of the third
planetary gear set and a fifth interconnecting member continuously
interconnects the ring gear member of the third planetary gear set with
the sun gear member of the fourth planetary gear set.

[0008]Further, a first torque transmitting device is selectively
engageable to interconnect the input member, the ring gear member of the
first planetary gear set, sun gear member of the second planetary gear
set and the sun gear member of the third planetary gear set with the ring
gear member of the fourth planetary gear set, a second torque
transmitting device is selectively engageable to interconnect the carrier
member of the second planetary gear set with the carrier member of the
fourth planetary gear set and the output member, a third torque
transmitting device is selectively engageable to interconnect the carrier
member of the first planetary gear set, the carrier member of the third
planetary gear set and the ring gear member of the second planetary gear
set with the stationary member, a fourth torque transmitting device is
selectively engageable to interconnect the sun gear member of the first
planetary gear set with the stationary member, a fifth torque
transmitting device is selectively engageable to interconnect the ring
gear member of the fourth planetary gear set with the stationary member,
and a sixth torque transmitting device is selectively engageable to
interconnect the ring gear member of the third planetary gear set and the
sun gear member of the fourth planetary gear set with the stationary
member. The torque transmitting devices are selectively engageable in
combinations of at least two to establish at least nine forward speed
ratios and at least one reverse speed ratio between the input member and
the output member.

[0009]It is thus an object of the present invention to provide a
transmission having four planetary gear sets.

[0010]It is a further object of the present invention to provide a
transmission having nine forward speeds and at least one reverse.

[0011]It is a still further object of the present invention to provide a
transmission having four planetary gear sets, a plurality of coupling
members and a plurality of torque transmitting devices.

[0012]Further objects, aspects and advantages of the present invention
will become apparent by reference to the following description and
appended drawings wherein like reference numbers refer to the same
component, element or feature.

DRAWINGS

[0013]The drawings described herein are for illustration purposes only and
are not intended to limit the scope of the present disclosure in any way.

[0014]FIG. 1 is a lever diagram of an embodiment of a nine speed
transmission according to the present invention;

[0015]FIG. 2 is a diagrammatic view of an embodiment of a nine speed
transmission according to the present invention; and

[0016]FIG. 3 is a truth table presenting the state of engagement of the
various torque transmitting elements in each of the available forward and
reverse speeds or gear ratios of the transmission illustrated in FIGS. 1
and 2.

DETAILED DESCRIPTION

[0017]The following description is merely exemplary in nature and is not
intended to limit the present disclosure, application, or uses.

[0018]At the outset, it should be appreciated that in the particular
example provided, the nine speed automatic transmission of the present
invention has an arrangement of permanent mechanical connections between
the elements of the four planetary gear sets. A first component or
element of a first planetary gear set is permanently coupled to a first
component or element of a third planetary gear set. A second component or
element of the first planetary gear set is permanently coupled to a
second component or element of a third planetary gear set. A first
component or element of the second planetary gear set is permanently
coupled to a first component or element of a third planetary gear set. A
third component or element of the second planetary gear set is
permanently coupled to a second component or element of a third planetary
gear set. Finally, a third component or element of the third planetary
gear set is permanently coupled to a third component or element of a
fourth planetary gear set.

[0019]Referring now to FIG. 1, an embodiment of a nine speed transmission
10 is illustrated in a lever diagram format. A lever diagram is a
schematic representation of the components of a mechanical device such as
an automatic transmission. Each individual lever represents a planetary
gear set wherein the three basic mechanical components of the planetary
gear set are each represented by a node. Therefore, a single lever
contains three nodes: one for the sun gear, one for the planet gear
carrier, and one for the ring gear. The relative length between the nodes
of each lever can be used to represent the ring-to-sun ratio of each
respective gear set. These lever ratios, in turn, are used to vary the
gear ratios of the transmission in order to achieve appropriate ratios
and ratio progression. Mechanical couplings or interconnections between
the nodes of the various planetary gear sets are illustrated by thin,
horizontal lines and torque transmitting devices such as clutches and
brakes are presented as interleaved fingers. If the device is a brake,
one set of the fingers is grounded. Further explanation of the format,
purpose and use of lever diagrams can be found in SAE Paper 810102, "The
Lever Analogy: A New Tool in Transmission Analysis" by Benford and
Leising which is hereby fully incorporated by reference.

[0020]The transmission 10 includes an input shaft or member 12, a first
planetary gear set 14 having three nodes: a first node 14A, a second node
14B and a third node 14C, a second planetary gear set 16 having three
nodes: a first node 16A, a second node 16B and a third node 16C, a third
planetary gear set 18 having three nodes: a first node 18A, a second node
18B and a third node 18C, a fourth planetary gear set 20 having three
nodes: a first node 20A, a second node 20B and a third node 20C and an
output shaft or member 22.

[0021]The input member 12 is coupled to the first node 14A of the first
planetary gear set 14. The first node 14A of the first planetary gear set
14 is coupled to the first node 18A of the third planetary gear set 18.
The second node 14B of the first planetary gear set 14 is coupled to the
second node 18B of the third planetary gear set 18. The first node 16A of
the second planetary gear set 16 is coupled to the first node 18A of the
third planetary gear set 18. The third node 16C of the second planetary
gear set 16 is coupled to the second node 18B of the third planetary gear
set 18. The third node 18C of the third planetary gear set 18 is coupled
to the third node 20C of the fourth planetary gear set 20. The output
member 22 is coupled to the first node 20A of the fourth planetary gear
set 20.

[0022]A first clutch 26 selectively connects the first node 14A of the
first planetary gear set 14 and the input member 12 with the second node
20B of the fourth planetary gear set 20. A second clutch 28 selectively
connects the second node 16B of the second planetary gear set 16 with the
first node 20A of the fourth planetary gear set 20 and the output member
22. A first brake 30 selectively connects the second node 14B of the
first planetary gear set 14, the third node 16C of the second planetary
gear set 16 and the second node 18B of the third planetary gear set 18
with a stationary element or a transmission housing 50. A second brake 32
selectively connects the third node 14C of the first planetary gear set
14 with a stationary element or a transmission housing 50. A third brake
34 selectively connects the second node 20B of the fourth planetary gear
set 20 with a stationary element or a transmission housing 50. A fourth
brake 36 selectively connects the third node 18C of the third planetary
gear set 18 and the third node 20C of the fourth planetary gear set 20
with the stationary element or the transmission housing 50.

[0023]Referring now to FIG. 2, a stick diagram presents a schematic layout
of the embodiment of the nine speed transmission 10 according to the
present invention. In FIG. 2, the numbering from the lever diagram of
FIG. 1 is carried over. The clutches, brakes, and couplings are
correspondingly presented whereas the nodes of the planetary gear sets
now appear as components of planetary gear sets such as sun gears, ring
gears, planet gears and planet gear carriers.

[0024]For example, the planetary gear set 14 includes a sun gear member
14C, a ring gear member 14A and a planet gear carrier member 14B that
rotatably supports a set of planet gears 14D (only one of which is
shown). The planet gears 14D are each configured to intermesh with both
the sun gear member 14C and the ring gear member 14A. The sun gear member
14C is connected for common rotation with a first shaft or
interconnecting member 42. The ring gear member 14A is connected for
common rotation with the input member 12 and with a second shaft or
interconnecting member 44. The planet carrier member 14B is connected for
common rotation with for common rotation with a third shaft or
interconnecting member 46.

[0025]The planetary gear set 16 includes a sun gear member 16A, a ring
gear member 16C and a planet gear carrier member 16B that rotatably
supports a set of planet gears 16D (only one of which is shown). The
planet gears 16D are each configured to intermesh with both the sun gear
member 16A and the ring gear member 16C. The sun gear member 16A is
connected for common rotation with a fourth shaft or interconnecting
member 48 and with the second shaft or interconnecting member 44. The
ring gear member 16C is connected for common rotation with a fifth shaft
or interconnecting member 52. The planet carrier member 16B is connected
for common rotation with a sixth shaft or interconnecting member 54.

[0026]The planetary gear set 18 includes a sun gear member 18A, a ring
gear member 18C and a planet gear carrier member 18B that rotatably
supports a set of planet gears 18D (only one of which is shown). The set
of planet gears 18D are each configured to intermesh with both the sun
gear member 18A and the ring gear member 18C. The sun gear member 18A is
connected for common rotation with the fourth shaft or interconnecting
member 48. The ring gear member 18C is connected for common rotation with
a seventh shaft or interconnecting member 56. The planet carrier member
18B is connected for common rotation with the fifth shaft or
interconnecting member 52 and the third shaft or interconnecting member
46.

[0027]The planetary gear set 20 includes a sun gear member 20C, a ring
gear member 20B and a planet gear carrier member 20A that rotatably
supports a first set of planet gears 20D (only one of which is shown) and
a second set of planet gears 20E (only one of which is shown). The first
set of planet gears 20D are each configured to intermesh with both the
sun gear member 20C and the second set of planet gears 20E. The second
set of planet gears 20E are each configured to intermesh with both the
ring gear member 20B and the first set of planet gears 20D. The sun gear
member 20C is connected for common rotation with an eighth shaft or
interconnecting member 58 and the seventh shaft or interconnecting member
56. The ring gear member 20B is connected for common rotation with a
ninth shaft or interconnecting member 60. The planet carrier member 20A
is connected for common rotation with a tenth shaft or interconnecting
member 62 and output member 22.

[0028]The input shaft or member 12 is continuously connected to an engine
(not shown) or to a turbine of a torque converter (not shown). The output
shaft or member 22 is continuously connected with the final drive unit or
transfer case (not shown).

[0029]The torque-transmitting mechanisms or the clutches 26, 28 and the
brakes 30, 32, 34 and 36 allow for selective interconnection of the
shafts or interconnecting members, members of the planetary gear sets and
the housing. For example, the first clutch 26 is selectively engageable
to connect the input shaft or member 12, the second shaft or
interconnecting member 44 and the ring gear member 14A of the first
planetary gear set 14 with the ninth shaft or interconnecting member 60.
The second clutch 28 is selectively engageable to connect the sixth shaft
or interconnecting member 54 with the tenth shaft or interconnecting
member 62. The first brake 30 is selectively engageable to connect the
third shaft or interconnecting member 46 with a stationary element or the
transmission housing 50 in order to prevent the third shaft or
interconnecting member 46 from rotating relative to the transmission
housing 50. The second brake 32 is selectively engageable to connect the
second shaft or interconnecting member 42 with a stationary element or
the transmission housing 50 in order to prevent the second shaft or
interconnecting member 42 from rotating relative to the transmission
housing 50. The third brake 34 is selectively engageable to connect the
ninth shaft or interconnecting member 60 with a stationary element or the
transmission housing 50 in order to prevent the ninth shaft or
interconnecting member 60 from rotating relative to the transmission
housing 50. The fourth brake 36 is selectively engageable to connect the
eighth shaft or interconnecting member 58 with a stationary element or
the transmission housing 50 in order to prevent the eighth shaft or
interconnecting member 58 from rotating relative to the transmission
housing 50.

[0030]Referring now to FIGS. 2 and 3, the operation of the embodiment of
the nine speed transmission 10 will be described. It will be appreciated
that the transmission 10 is capable of transmitting torque from the input
shaft or member 12 to the output shaft or member 22 in at least nine
forward speed or torque ratios and at least one reverse speed or torque
ratio with a triple overdrive. Each forward and reverse speed or torque
ratio is attained by engagement of one or more of the torque-transmitting
mechanisms (i.e. first clutch 26, second clutch 28, first brake 30,
second brake 32, third brake 34 and fourth brake 36), as will be
explained below. FIG. 3 is a truth table presenting the various
combinations of torque-transmitting elements that are activated or
engaged to achieve the various gear states. Actual numerical gear ratios
of the various gear states are also presented although it should be
appreciated that these numerical values are exemplary only and that they
may be adjusted over significant ranges to accommodate various
applications and operational criteria of the transmission 10. An example
of the gear ratios that may be obtained using the embodiments of the
present invention are also shown in FIG. 3. Of course, other gear ratios
are achievable depending on the gear diameter, gear teeth count and gear
configuration selected.

[0031]To establish reverse gear, the second brake 32 and the third brake
34 are engaged or activated. The second brake 32 connects the second
shaft or interconnecting member 42 with a stationary element or the
transmission housing 50 in order to prevent the second shaft or
interconnecting member 42 from rotating relative to the transmission
housing 50. The third brake 34 connects the ninth shaft or
interconnecting member 60 with a stationary element or the transmission
housing 50 in order to prevent the ninth shaft or interconnecting member
60 from rotating relative to the transmission housing 50. Likewise, the
nine forward ratios are achieved through different combinations of clutch
and brake engagement, as shown in FIG. 3.

[0032]It will be appreciated that the foregoing explanation of operation
and gear states of the nine speed transmission 10 assumes, first of all,
that all the clutches and brakes not specifically referenced in a given
gear state are inactive or disengaged and, second of all, that during
gear shifts, i.e., changes of gear state, between at least adjacent gear
states, a clutch or brake engaged or activated in both gear states will
remain engaged or activated.

[0033]The description of the invention is merely exemplary in nature and
variations that do not depart from the gist of the invention are intended
to be within the scope of the invention. Such variations are not to be
regarded as a departure from the spirit and scope of the invention.